Revert "Add msw.window.no-composited system option"

This reverts commit d9734baed5.

docs/changes.txt

@@ -11,19 +11,6 @@ INCOMPATIBLE CHANGES SINCE 3.2.x:
 Changes in behaviour not resulting in compilation errors
 --------------------------------------------------------
 
-- wxMSW now uses double buffering by default, meaning that updating the
-  windows using wxClientDC doesn't work any longer, which is consistent with
-  the behaviour of wxGTK with Wayland backend and of wxOSX, but not with the
-  traditional historic behaviour of wxMSW (or wxGTK/X11). You may call
-  MSWDisableComposited() to restore the previous behaviour, however it is
-  strongly recommended to change your redrawing logic to avoid using wxClientDC
-  instead, as the code using it still won't work with wxGTK/wxOSX.
-
-  You may also choose to globally set the new msw.window.no-composited system
-  option to disable the use of double buffering, but please consider doing it
-  only as a last resort and/or temporary solution, as this _will_ result in
-  flicker and won't be supported at all in the future wxWidgets versions.
-
 - wxMSW doesn't support versions of Microsoft Windows before Windows 7. If you
   need Windows XP or Vista support, please use wxWidgets 3.2.
 

interface/wx/sysopt.h

@@ -82,10 +82,6 @@
         appearance but not all fonts are available in this quality,
         e.g. the Terminal font in small sizes is not and this option may be
         used if wider fonts selection is more important than higher quality.
-    @flag{msw.window.no-composited}
-        If set to 1, disables the use of composited, i.e. double-buffered,
-        windows by default in wxMSW. This is not recommended, but can be useful
-        for debugging or working around redraw problems in the existing code.
     @flag{msw.dark-mode}
         If set to 1, enable experimental support of dark mode if the system is
         using it, i.e. this has the same effect as calling

src/msw/window.cpp

@@ -482,11 +482,7 @@ bool wxWindowMSW::CreateUsingMSWClass(const wxChar* classname,
     // checking it it's already set for the parent, even though we could.
     if ( !classname )
     {
-        // We also allow disabling the use of this style globally by setting
-        // a system option if nothing else (i.e. turning it off for individual
-        // windows) works.
-        if ( !wxSystemOptions::GetOptionInt("msw.window.no-composited") )
-            exstyle |= WS_EX_COMPOSITED;
+        exstyle |= WS_EX_COMPOSITED;
     }
 
     if ( IsShown() )